This invention relates to a light source apparatus for an endoscope and, more particularly, to an external light source apparatus used for endoscopic photographing.
Generally, endoscopic photographing is effected concurrently when a body cavity is observed with an endoscope. In endoscopic photographing, the object to be photographed is completely dark so that a shutter need not be provided on the camera, but as a shutter release operation it is only necessary to block light from a light source. For this reason, in the light source apparatus for an endoscope a shutter plate is provided between the light source and a light transmitting means for transmitting light from the light source to an objective lens section in the endoscope. For taking the endoscopic picture an ordinary still camera may be provided at an eyepiece section of the endoscope. During the photographing, the shutter plate of the light source apparatus is held released by a drive means such as a rotary solenoid. Therefore, if the exposure is made for a long time, the drive means is rendered into an overload state. Generally, in endoscopic photographing the object to be photographed is completely dark, and a considerably long time is required for the exposure, so that the afore-mentioned inconvenience arises. Further, while it is required to take pictures at a short interval for examining changes of the affected part of the body, in this case the light source has to be repeatedly on-off operated. This is undesired from the standpoint of the service life of the light source if a discharge lamp is used as the light source.
An object of the invention is to provide a light source apparatus for an endoscope, in which power supplied is controlled for preventing the overload state of the discharge lamp and shutter plate.